Installer behaves differently when booted in BIOS vs EFI

[Jeff Lane ]

One of our hardware partners has been testing ISO installs and discovered that the boot behavior is different depending on how you boot the machine.

For example, if you boot the ISO while in BIOS/Legacy mode, you get (at least for a while) the familiar splash screen with the Keyboard and little person icons at the bottom, that if you don't keypress opens the installer with defaults of English locale settings, or if you do hit a key, you get the menus to choose language and keyboard before you get the grub menu with all the various installer boot options.

BUT if you set the machine to boot in EFI mode, you get none of that and go straight into the installer.

So there's a bit of inconsistency when booting the ISO image. They reported this to me after seeing in on a couple different servers, and recreated it using both 18.04.4 and Focal ISOs.

I also recreated this in KVM VMs by booting the ISOs in both BIOS and EFI modes.

[Jeff Lane  (bladernr)]

this PNG is what you first see when booting in BIOS mode.

[Jeff Lane  (bladernr)]

and this is what you see when you boot into EFI mode, so the installer experience is completely diffrent. (Maybe it's a technical limitation, but it was confusing enough to the engineers who reported it to me that I wanted to bring it up here).

[Jeff Lane  (bladernr)]

Also, it should be noted that the behaviour in BIOS mode is a bit odd too... on bare metal, their complaint was that the aubergine splash screen sat for a while, then it booted into the GA kernel (18.04.4 ISO) never giving them the chance to choose HWE. FWIW, they didn't know to press a key to get a grub menu until I told them they needed to.

BUT on my VM testing, this wasn't the case... so it's possible they just hit enter a bunch of times and got passed this. I'm opening this for them, but will leave it for them to comment on and if not, just close it.

[Michael Hudson-Doyle (mwhudson)]

You should definitely see a grub menu (with a timeout of iirc 5s) in UEFI mode. If they don't on their hardware then there is some grub problem (of course if their hardware is the sort that takes 15 minutes to post, then missing a 5s menu is very easy).

The difference between BIOS and UEFI boots is known, and imo should probably be fixed by getting rid of isolinux and just having grub everywhere.

[Michael Hudson-Doyle (mwhudson)]

Not sure if there's really a bug here?

[Jeff Lane  (bladernr)]

Honestly, they never commented back, so I'll just close it. They haven't even mentioned this in a long while, so ... eh.